package com.itheima.reggie.controller;

import cn.hutool.core.io.IoUtil;
import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;

import java.io.IOException;
import java.util.UUID;

/**
 * 文件上传和下载
 */
@RestController
@RequestMapping("/common") //映射路径
@Slf4j
public class CommonController {

    @Value("${reggie.path}")
    private String basePath;
    /**
     * 上传文件
     * @param file
     * @return
     */
    @PostMapping("/upload")
    public R<String> upload(MultipartFile file){
        //file是一个临时文件，需要转存到指定位置，否则本次临时请求后临时文件会删除
        log.info(file.toString());
        //原始文件名
        String originalFilename = file.getOriginalFilename();
        String substring = originalFilename.substring(originalFilename.lastIndexOf("."));
        //使用UUID重新生成文件名，防止文件名重复造成文件覆盖
        String filename = UUID.randomUUID().toString() + substring;

        //创建一个文件对象
        File dir = new File(basePath);
        //判断当前目录是否存在，不存在则创建
        if(!dir.exists()){
            dir.mkdirs();
    }
        try {
            //将临时文件转存到指定位置
            file.transferTo(new File(basePath+filename));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return R.success(filename);
    }

    /**
     * 文件下载
     * @param name
     * @param response
     */
    @GetMapping("/download")
    public void download(String name, HttpServletResponse response){
        try {
            //输入流，通过输入流读取文件内容
            FileInputStream fileInputStream = new FileInputStream(new File(basePath + name));

            //输出流，通过输出流将文件写回浏览器
            ServletOutputStream outputStream = response.getOutputStream();

            response.setContentType("image/jpeg");

            /*int len = 0;
            byte[] bytes = new byte[1024];
            while ((len = fileInputStream.read(bytes)) != -1){
                outputStream.write(bytes,0,len);
                outputStream.flush();
            }*/
            //把输入流的文件拷贝到输出流
            IoUtil.copy(fileInputStream,outputStream);
            //关闭资源
            outputStream.close();
            fileInputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
